Among the most appreciated musky ingredients known in the art of perfumery, muscone (or 3-methyl-cyclopentadecanone) and EXALTONE.RTM. (or cyclopentadecanone) have acquired a special renown. In an attempt to develop a large scale preparation of these derivatives, hitherto numerous synthetic approaches have been devised [see e.g. Cosmetics and Perfumery, 88, 67(1973)]. In spite of this undertaking no economical synthetic process has been satisfactorily applied so far to their industrial preparation.
Among the variety of processes known, one may cite the following: ##STR3##
By making the preparation of certain critical intermediates easier, the novel process of the present invention provides an original solution to the problem of economically synthetizing macrocyclic ketones.